Fluid-operated hoist



March 14, 1950 c. D. P. SMALLPEICE 254M FLUID-OPERATED HOI'ST Filed Oct.27, 1948 2 Shets-Sheet 1 I Invenfor CUfiBYQ PSMAZLPf/CE y ma wwg C. D.P. SMALLPEICE FLUID-OPERATED HOIST 2 SheetsQSheet 2 Filed Oct. 27, 1948Inventor C0559 D. 5M/lllpf/C'f Attornejj Patented Mar. 14, 1950 UNITEDSTATES OFFICE FLUID-OPERATED HQIST Cosby D. P. Smallpeice, SwanwickShore, Southampton, England 6 Claims. 1

This invention relates to a fluid-operated hoist (e. g., to a hoist-andthis term is used in a generic sense-to be operated by compressed air,steam. or hydraulic pressure), and is an improvement in or modificationof that disclosed in my United States patent specification No. 663,729,filed April 20, 1946.

This prior specification describes a hoist including a cylinder, afluid-pressure-responsive piston reciprocable in one end of the cylinderand carrying a piston rod the free end of which is guided in the otherend of the cylinder and carries a pulley or pulley set, a stationarypulley or pulley set within the cylinder beyond the limit of the pistontravel, a hoisting cable having one end anchored and the other endextending through an opening in the cylinder after passing round the twopulleys or pulley sets, and controllable means for supplying operatingfiuid to the end of the cylinder remote from that in which the movablepulley or pulley set is guided.

My main object is to provide an improved hoist of this kind with whichthe speed of lowering the load can, if desired, be increased, or thespeed of lifting, particularly in the case of a light load, can berestricted.

According to the invention, a hoisting apparatus includes substantiallysimilar coaxial cylinder portions, with the remote ends closed,separated by a portion carrying a stationary pulley set, a movablepulley set within one cylinder portion, a hoisting cable, passing roundthe pulley sets, having one end anchored and a hanging portion extendingfrom between the cylinder portions, fiuid-pressure-responsive plungers,with the pulley sets between them, respectively reciprocable in thecylinder portions and interconnected for movement in unison, the movablepulley set being fast with the adjacent plunger, and controllable meansfor selectively supplying fiuid under pressure to the remote ends of thecylinder portions and for regulating the discharge of fluid from thesaid remote ends.

In addition, I may combine with either or with both of thesaid remoteends, or with the con trollable means, a valve which is normally open toa slight degree and which is adapted to be closed to a material extentwhen subjected to a substantial pressure rise, thus to provide only aleakage path, as when the fluid pressure is applied to the associatedend to force the adjacent plunger outwardly therefrom.

In the accompanying drawings-- Figure 1 is a plan of a hoistingapparatus, ac-

cording to the invention, with various portions shown broken away.

Figures 2 and 3 are fragmentary cross-sections,

taken on the lines 22 and 33 of Figure 1, respectively.

Figure 4 is an enlarged view of the automatic valve shown on the righthand end of Figure 1; and

Figure 5 is a perspective view of the apparatus with parts cut away.

In order not to confuse the drawings the hoisting cable has been omittedfrom Figures 1, 2 and 3.

In carrying out the invention, there are two cylinder portions, A and B,which are spaced from one another by a block ll carrying a stationarypulley set 20, 20. As shown, the two cylinder portions includeindividual cylinders l2, 13, the adjacent ends of which abut the block II. The remote ends of the cylinder portions are closed by plates l5, 16held in position by tie rods H, I! and nuts I8, ill, the tie rods alsoserving for locating the adjacent ends of the cylinder portions againstthe block H.

The stationary pulley set comprises an appropriate number of pulleys 2U,20 each mounted through a ball bearing 2|, 2! upon a common spindle 22carried by a block I l, to which latter is secured a bolt 23 with asupporting eye whereby the hoisting apparatus can be suspended in asubstantially horizontal position.

In a rather similar manner a movable pulley set comprises a number ofpulleys 25, 25 each mounted through ball bearings upon a common spindle26 carried by a block 21 which is slidable within the cylinder portionB. The right-hand end (Figure 1) of the block 2'! serves as afluidpressure-responsive plunger, for which purpose it is shown as beingfitted with a fieigible sealing ring 28 acting upon the wall of thecylinder portion B in a manner known per se.

The hanging portion 30 (Figure 5) of a hoisting cable passes through anopening 3| in the stationary block H and then over the adjacent endpulley 20, thence to a corresponding pulley 25 in the movable set, thenback to the next pulley in the stationary set, and so on, until. finallythe cable is anchored. With an equal number of pulleys in each set thecable may be anchored to a pin 33 carried by the stationary block II. Ifthere is one more pulley in the stationary set than in the movable setthe cable will preferably be carried forward again to the movable block2'! to be anchored thereto in a corresponding manner.

Disposed in the cylinder portion A is a plunger 3 35 fitted, again in aknown manner, with a sealing ring 36.

The plunger 35 and block plunger 2i are rigidly interconnected formovement in unison by spaced piston rods 37, 31 which pass outside thestationary pulley set through openings 38 provided for the purpose inthe stationary block H, as indicated by Figure 2.

It will be understood that when fluid under pressure is admitted to theleft-hand end of the cylinder portion A the plunger 35 will be driven tothe right, carrying with it the movable set of pulleys 25, 25 andthereby raising the hanging end of the hoisting cable and any loadthereon. During this action air in the cylinder portion B escapedthrough an automatic valve 39 which is shown as being provided in theend wall H3. This automatic valve is biassed to a position (see Figure4) in which it is open only to a slight degree by means of a spring 40.

In the event, however, that fluid pressure should be admitted to theleft-hand end of the cylinder portion A at a time when there is no loadon the hoisting cable, the hanging end of the latter will tend to beraised very quickly,

and it is the purpose of the automatic valve 39 to prevent the possbility of damage or shock occurring in these conditions. In the saidconditions the pressure rise in the cylinder portion B serves foroperating the valve disc #2 in the closing direction, the pressurediiierences thereon maintaining it in this position. The valve does notclose completely, however, the disc 42 being provided with a washer 43which will prevent the disc 42 from providing a complete seal, this leakbeing suflicient to allow the operation of the hoisting apparatus in thelifting direction when no load is being lifted.

Whilst the manner in which fluid pressure can be supplied to either ofthe remote ends of the cylinder portions A or B forms no part of thepresent invention, the drawings show two flexible pipe lines t5, t6interconnecting each end and a trigger valve 47 (Figure to which isconnected a pipe 48 for the supply of fluid under pressure. The triggervalve has two operating members 49, 5B, Depression to one of thesemembers serves for supplying fluid pressure to the appropriate end ofthe selected cylinder portion,

and depression of the other serves for connecting this end to exhaust.

By making provision for the supply of fluid pressure to the right-handend of the cylinder portion B it is possible to accelerate the loweringof the hanging end of the hoisting cable in those cases when there is noload on the cable, the sudden pressure rise in the cylinder portion Bserving for closing the automatic valve 39, except for the small leak,in the manner described above.

In some cases also it may be, advisable to provide the cylinder portionA with an automatic valve, as indicated at 52, which is similar in allrespects to the valve, 39. When lowering a load by the application offluid pressure tothe cylinder portion B the automatic valve 52 willclose, except for the aforesaid leak if the lowering shouldv be effectedat a speed which is too great.

Naturally, when raising a load the fluid pressure applied to thecylinder portionv A will close the automatic valve 52 in the mannerdescribed in connection with the automatic valve 39.

What I claim as my invention and desire to secure by Letters Patent oftheUnited States is:

1. Hoisting apparatu including substantially similar coaxial cylindersarranged end-to-end and with the remote ends closed, said cylindersseparated by a portion carrying a stationary pulley set, a movablepulley set guided within one cylinder, a hoisting cable, passing roundthe pulley sets, having one end anchored and having a hanging portionextending from between the cylinders, a fluid-pressure-responsiveplunger reciprocabe in the other cylinder and interconnected with themovable pulley set for movement in unison, and controllable means forsupplying fluid under pressure to the appropriate end of the cylinder inwhich said plunger works to actuate said plunger.

2. Hoisting apparatus including substantially similar coaxial cylindersarranged end-to-end and with the remote ends closed, said cylindersseparated by a portion carrying a stationary pulley set, a movablepulley set within one cylinder, a hoisting cable, passing round thepulley sets, having one end anchored and having a hanging portionextending from between the cylinders, fluid-pressure-responsiveplungers, with the pulley sets between them, respectively reciprocablein the cylinders and interconnected for movement in unison, the movablepulley set being fast with the adjacent plunger, and controllable meansfor selectively supplying fluid under pressure to the remote ends of thecylinders and for regulating the discharge of fluid from said remoteends.

3. Hoisting apparatus including substantially similar coaxial cylinderportions arranged endto-end and with the remote ends closed, astationary pulley set mounted substantially centrally within saidcylinder portions, a movable pulley set within one cylinder portion, ahoisting cable, passing round the pulley sets, having one end anchoredand having a hanging portion extending to the outside of said cylinderportions, fluidpressure-responsive plungers, with the pulley setsbetween them, respectivel reciprocable in said cylinder portions andinterconnected for movcment in unison, the movable pulley set being fastwith the adjacent plunger, and controllable means for selectivelysupplying fluid under pressure to the remote ends of the cylinderportions and for regulating the discharge of fluid from said remoteends.

4, Hoisting apparatus including substantially similar coaxial cylinderportions arranged end-toend and with the remote ends closed, astationary pulley set mounted substantially centrally within saidcylinder portions, a movable pulley set within one cyl'nder portion, ahoisting cable, passing round the pulley sets, having one end anchoredand having a hanging portion extending to the outside of said cylinderportions, fluid-pressureresponsive plungers, with the pulley setsbetween them, respectively reciprocable in said cylinder portions andinterconnected for movement in unison, the movable pulley set being lastwith the adjacent plunger, controllable means for selectively supplyingfluid under. pressure to the remote ends of the cylinder portions, andautomatic valves for regulating thev discharge of fluid from the saidremote ends, said valves being normally open to a small degree andadapted to close to a material extent when subjected to a substantialpressure rise.

5. Hoisting apparatus, according to claim 1, and in which the closed endof the cylinder in which the movable pulley set works is provided with anormally-open. automatic valve adapted nearly to close when subjected toa substantial pressure rise.

6. Hoisting apparatus including substantially similar coaxial cylindersarranged end-to-end and, with the remote ends closed, said cylindersseparated by a block carrying a stationary pulley set, plates closingthe remote ends of said cylinders, said plates, cylinders and block allbolted together, a movable pulley set within one cylinder, a hoistingcable, passing round the pulley sets, having one end anchored and havinga hanging portion extending from between said block,fluidpressure-responsive plungers, with the pulley sets between them,respectively reciprocable in said cylinders and interconnected formovement in unison, the movable pulley set being fast with the adjacentplunger, and controllable means for selectively supplying fluid underpressure through said plates and for regulating the discharge of fluidfrom said plates.

COSBY D. P. SMALLPEICE.

REFERENCES CITED The following references are of record in the file ofthis patent:

UNITED STATES PATENTS Number Name Date 981,268 Hurd Jan. 10 19111,188,760 Hagenbucher June 2'7, 1916

